What is the meaning of Dervish?

An itinerant Sufi mystic practicing voluntary poverty in devotion to God, and often engaging in ecstatic rituals.

A citizen or inhabitant of Darawiish (circa 1895–1920 C.E.), an anti-colonial polity in modern Somalia headed by Sufis.

One of the followers of Muhammad Ahmad, the Mahdi of the Sudan, in the 1880s.

Any irregular guerrilla fighter resembling the Sudanese Mahdi in equipment, uniform, tactics, etc.

Source: wiktionary.org